Lubricating devices for sewing machines



25, 1956 H. F. SCHAEFER, JR 2,754,113 LUBRICATING DEVICES FOR SEWING MACHINES Filed July 16, 1954 2 Sheets-Sheet l Q j Q 75 76 m 1956 H. F. SCHAEFER, m 22,764,113

LUBRICATING DEVICES FOR SEWING MACHINES Filed July 16, 1954 2 Sheets-Sheet 2 n Mr Hams Jc/zcze/e, Jr.

United States Patent LUBRICATWG DEVICES FOR SEWING MACHINES Hans F. Schaefer, Jr., Rockport, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. 1., a corporation of New Jersey Application July 16, 1954, Serial No. 443,807

Claims. (Cl. 112-256) The present invention relates to improvements in lockstitch sewing machines adapted to operate upon marginal portions of a shoe, in which a shoe upper and a sock lining attached to a platform sole and platform wrapper or sole cover strip are sewn together with a lockstitch seam passing through all the parts except the platform sole. The present invention is an improvement on a machine for this purpose described in an application for United States Letters Patent, Serial No. 297,216, filed July 5, 1952, in the names of Hans F. Schaefer, Jr. and Frank Pulsifer. In certain aspects the invention is applicable to shoe sewing machines of other types intended for operations other than those performed upon shoes.

In the machine of the inventors application, above identified, operating mechanisms for the loop taker and other stitch forming devices are located within a twocompartment, oil-retaining housing within a machine enclosing frame. To facilitate the lubrication of the operating mechanisms that machine is provided with a continually circulating lubricating system within its frame, in which a dual level oil sump is maintained. However, for obvious reasons, the loop taker is located outside the machine frame and the lubricating compartments. Thus, while the operating mechanisms are adequately lubricated from within, the loop taker being located outside the machine frame requires separate and limited lubrication to be applied manually. To apply lubricant manually to the loop taker is not satisfactory, firstly because it is inconvenient and time consuming, the operator being required to mannipulate an oil can or other conventional lubricating means and, secondly because the quantity of lubricant, generally a small amount, is never delivered with any degree of accuracy, oftentimes too much or too little being used. Too much lubricant contaminates the thread supply, the shoe or other object being sewn. On the other hand, too little oil causes improper operation of and damage to the machine. Also, the particular time at which the lubricant is added manually is purely arbitarary and at the discretion of the operator, the effectiveness of the lubrication being dependent upon the extent to which the operator is successful in forming a fixed habit of regularity in application of lubricant.

Accordingly, one of the objects of this invention is to produce means for supplying lubricant to a loop taker of a sewing machine with accuracy in minute quantities proportioned to the actual operations and to the amount of thread consumed.

A second object is to provide lubricating means occupying a minimum of space in a sewing machine of the type referred to while utilizing as much of the existent machine structure as possible.

In accordance with the objects noted above, the machine embodying the present invention is of the lockstitch type and includes the usual stitch forming devices, of which a rotary loop taker has an internal raceway and a locking thread supply case mounted therein with a holder for a supply of locking thread within the thread case, and means for ejecting the holder from the thread case after "ice the thread supply is exhausted, in which lubricating means are provided and arranged to be actuated by the ejecting means for supplying a limited quantity of lubricant to the thread case raceway each time the supply holder is ejected for replenishment. Preferably, the lubricating means consists of an elementary form of pump comprising an absorbent member and means for expressing lubricant from the absorbent member whenever the ejecting means is actuated.

Other features of the invention are embodied in the combinations and arrangements of the parts, hereinafter described and claimed, the advantages of which will readily be understood from the following detailed specification taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of the sewing head portion of a machine embodying the invention with parts covering the loop taker broken away and shown in section;

Fig. 2 is a plan view of a cover plate and thread holder ejector handle in the machine shown in Fig. 1;

Fig. 3 is a rear elevation showing the driving mechanism for the loop taker arranged in a two-compartment oil retaining housing;

Fig. 4 is a plan view showing the loop taker on an enlarged scale with parts broken away and shown in section;

Fig. 5 is a front elevation and partly in section of the loop taker with the thread case and thread holder removed as viewed in the direction of the arrow in Fig. 1;

Fig. 6 is a detail sectional elevation of an oil orifice disk taken along the line VI--VI of Fig. 4; and

Fig. 7 is a detail sectional view on an enlarged scale of the loop taker and its mounting shaft with the thread case and the thread holder in place.

The apparatus illustrated in the drawings is a lockstitch sewing machine adapted to operate upon the marginal portions of a slip-lasted shoe, having an upper, a sock lining and a wrapper or platform cover strip.

The general arrangement of the machine is such that the greatest amount of space possible is available about the point of operation of the stitch forming devices consistent with effective design for reliable sewing. In a lockstitch shoe sewing machine having a shuttle or loop taker the greatest space is available about the sewing point when the loop taker is located below the level of the work presented to the machine where there is no possibility of its interference with the operators line of vi- S1011.

The stitch forming devices of the machine comprise a loop taker or shuttle 2 which is of the hollow discoidal rotary type having a needle loop entering beak 3 and a guard 4 (Fig. 5) and a curved eye-pointed needle 5, the eye of which carries a thread 6 (Fig. 1). Within the loop taker is an open ended circular locking thread supply case 8 rotatably mounted in the shuttle. For driving the loop taker 2 a hollow shaft 10 is provided to which the loop taker is rigidly connected, the shaft being mounted in bearings 12 and 14 in the main frame of the machine. To the inner end of the loop taker shaft is secured a bevel gear 16 meshing with a second bevel gear 18 secured to a countershaft 20. For mounting the thread supply case 8 in the loop taker 2, the loop taker is formed with a raceway 22 in which a flange-on the thread case is engaged. Removably supported inside the thread case is a locking thread supply holder comprising a bobbin or reel 24 providing sufficient capacity of thread, indicated at 26, for sewing a number of shoes.

The locking thread supply holder, in addition to the bobbin 24 includes a cover 28 fitting the front face of the thread case and having a central hub of sufficient length to enter a central opening in the bobbin or reel 24. The thread case itself has a corresponding hub of shorter length also entering within the reel 24 but providing a somewhat looser support for the reel than is afforded by the hub on the cover, so that when the cover 28 is removed from the thread case the reel 24 is carried with it. Thus, the reel 24 and cover 28 are removable as a unit from the thread case whenever it is necessary to renew the supply of locking thread 26.

To secure the supply holder to the thread case the hubs of the cover 28 and of the thread case 8 have alined central passages within which is located a latch 30 engaging a detent in the form of a shoulder within a counterbore in the rear wall of the thread case surrounding its central passage. The latch 30 has a flexible central portion and a shank secured Within the central passage of the cover 28, the arrangement being such that the latch is disengaged from the detent in the thread case to release the holder.

To eject a locking thread reel from the thread case after exhaustion of the supply, the free end of the latch 30 has an inclined surface with which a conical head on an ejector rod 36 is engaged. The ejector rod is mounted in bearings 32 and 34 within the hollow loop taker shaft and is slidably mounted therein to move toward and from the latch on the thread case cover 28. During normal sewing operations the conical head on the ejector rod 36 is withdrawn from engagement with the latch 30 through the action of a pair of springs 38 and 4t) surrounding the rearward end of the ejector rod. Thus, the rod does not interfere with passage of each loop of needle thread about the thread case. The spring 38 is mounted within a circular recess formed at one end of a counterbored nut 42 threaded on the rearward end of the loop taker shaft 10 serving to secure the beveled gear 16 to the shaft. Between the springs 38 and is slidably mounted upon the ejector rod a washer 44 and the spring 40 is confined under a preliminary compression by a hollow cap 46 pinned to the ejector rod.

For actuating the ejector rod against the latch 30 to release it from the detent and to eject the bobbin 24 from the thread case the rearward end of the rod is engaged by a rounded portion on an arm 48 secured to a vertical shaft 50 rotatably mounted in a bearing formed in a horizontal cover plate 52 attached to the machine frame by screws 54, best shown in Figs. 2 and 3. Above the cover plate 52 is an ejector actuating handle 56 rigidly secured to the shaft 50. When the handle 56 is rotated the rod 36 is shifted against the latch 30 forcing the thread holder from the thread case.

It has been found that during normal operation of a lockstitch shoe sewing machine the need for lubrication of any of the parts bears a direct relationship to the amount of thread consumed during sewing operations. For this reason it is common for an operator of a shoe sewing machine to lubricate certain parts of his machine each time the supply of locking thread is replenished. But even with extreme care on the part of the operator there is no positive assurance that excess or inadequate lubrication will be avoided.

In accordance with the present invention a predetermined amount of lubricant is caused to flow to the thread case raceway in the loop taker of the illustrated machine automatically each time an empty locking thread supply reel is ejected from the thread case, so that the operator of the machine is no longer subject to the requirements of habitual application of lubricant to the raceway. For this purpose the rod 36 for ejecting the holder comprising the locking thread supply reel and cover 28 has mounted upon it between the washer 44 and a circular disc 58 a wad of absorbent material in the form of a circular felt washer 60. The washer 60 is of such diameter that it fits closely to that of the counterbore, indicated at 62, in the nut 42, the counterbore serving-as a cylinder to confine the wad and the washer serving as a plunger of a lubricating pump. Thus, the lubricant expressed is subjected to sufficient pressure to reach the loop taker through the loop taker shaft.

The lubricating pump is actuated by the plate 44 which compresses the absorbent washer 60 and expresses lubricant therefrom causing it to flow through the bearings 32 and 34 within the loop taker shaft 10 and through suitable intersecting passages 61 and 63 in the body of the loop taker leading to the outer edge of the raceway 22. Each time a bobbin is ejected from the thread case the cap 46 compresses the washer 60. The spring 40 is first compressed when a sleeve portion of the cap 46 engages the washer 44 and thereafter the absorbent washer 66* itself is compressed. To express lubricant from the absorbent washer the disc 58 engages a shoulder at the base of the counterbore 62 which limits its further movement and the disc being provided with perforations 64 permits expression of lubricant into a second counterbore 65 of reduced diameter in the nut 42. The lubricant passes from the reduced counterbore 65 through grooves 66 and 68 in the ejector rod 36 and through a conical recess '70 surrounding the forward end of the ejector rod thence into the passages 61 and 63 leading to the raceway.

To limit the quantity of lubricant flowing into the raceway in the loop taker the groove 66 in the rod 36 is of such length that it blocks passage of lubricant flow when the rod is in fully actuated position. When moved from the position of Fig. 4 to its fully actuated position the rod 36 and the bearing 34 in the loop taker shaft thus act as a metering device, the end of the groove 66 and the bearing acting as a cutoff valve.

After expressing the lubricant the disc 58 and the absorbent wad or washer are retracted from the counterbore cylinder in the nut 42 by the springs 38 and 40 aided by the engagement of a snap ring 72 adjacent to the plate 58 and fitted within a circumferential groove in the shaft 36. To insure proper reabsorption of lubricant the washer is moved bodily out of the 'counterbore 62 where, aside from the spring 38 which acts as a guard, the washer is exposed about its entire periphery.

To apply lubricant to the absorbent washer 60 a supply conduit 74 leads to .a point just above the washer and extends from a groove 76 in a portion of the machine frame. Above the groove 76 is located the downwardly bent end of a second conduit 78 supported by a narrow rectangular casing 80 into which lubricant is thrown by centrifugal force during operation of the machine by the rotating part 82 which dips into a sump 84, more fully described in inventors prior application above identified. By the existence of conduits 74 and 78 the periphery of the absorbent washer 60 is continuously saturated with lubricant so that at any time it may be compressed to express the lubricant and force it through the grooves and passages into the thread case raceway.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

1. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder for a supply of locking thread in the thread case, means for ejecting the holder from the thread case, and lubricating means actuated by the ejecting means and directed toward said raceway for causing lubricant to flow to the raceway each time the holder is ejected.

2. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder for a supply of locking thread in the thread case including a bobbin, means for ejecting the bobbin from the thread case, and a lubricating pump actuated by the ejecting means and directed toward said raceway for causing lubricant to flow to the raceway each time the bobbin is ejected.

and a cover fitting the thread case, a latch and detent for securing the cover to the thread case, an ejector for releasing the latch and ejecting the bobbin from the thread case, and a lubricating pump actuated by the ejector and directed toward said raceway for causing lubricant to flow to the raceway each time the bobbin is ejected.

4. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder for a supply of locking thread in the thread case including a bobbin and a cover fitting the thread case, a latch and detent for securing the cover to the thread case, a hollow shaft operably connected to the loop taker for imparting rotation thereto, an ejector comprising a rod slidable in said hollow shaft and having a portion engageable with the latch to release the latch from the detent and eject the bobbin from the thread case, and a lubricating pump carried by the rod for causing lubricant to flow through the shaft to the thread case raceway each time the bobbin is ejected from the thread case.

5. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder for a supply of locking thread in the thread case including a bobbin and a cover fitting the thread case, a latch and detent for securing the cover to the thread case, a hollow shaft operably connected to the loop taker for imparting rotation thereto, an ejector comprising a rod slidable in said hollow shaft and having a portion engageable with the latch to release the latch from the detent and eject the bobbin from the thread case, and a lubricating pump carried by the rod for causing lubricant to flow through the shaft to the thread case raceway each time the bobbin is ejected from the thread case, said rod being grooved along its length to provide passage for the lubricant from the pump to the raceway in the loop taker.

6. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder for a supply of locking thread in the thread case including a bobbin and a cover fitting the thread case, a latch and detent for securing the cover to the thread case, a hollow shaft operably connected to the loop taker for imparting rotation thereto, an ejector comprising a rod slidable in said hollow shaft and having a portion engageable with the latch to release the latch from the detent and eject the bobbin from the thread case, a lubricating pump carried by the rod for causing lubricant to flow through the shaft to the thread case raceway each time the bobbin is ejected from the thread case, and a metering valve consisting of a bearing in the loop taker shaft for the ejector rod and a groove in the ejector rod of a length to admit passage of lubricant through the bearing in the loop taker shaft in one position of the ejector rod and to block the passage of lubricant in another position of the ejector rod.

7. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder comprising a bobbin for a supply of locking thread in the thread case, releasable means for securing the bobbin in the thread case, a hollow shaft on which the loop taker is mounted, an ejector rod slidable in the loop taker shaft and having a portion engageable with the releasable means for ejecting the bobbin from the thread case, and a pump for causing lubricant to flow to the raceway in the loop taker, comprising a wad of absorbent material mounted on the ejector rod and means actuated by the rod for expressing lubricant from the wad to force lubricant into the raceway for the thread case.

8. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder comprising a bobbin for a supply of locking thread in the thread case, releasable means for securing the bobbin in the thread case, a hollow shaft on which the loop taker is mounted, an ejector rod slidable in the loop taker shaft and having a portion engageable with the releasable means for ejecting the bobbin from the thread case, a pump for causing lubricant to flow to the raceway in the loop taker, comprising a wad of absorbent material mounted on the ejector rod and means actuated by the rod for expressing lubricant from the wad to force lubricant into the raceway for the thread case, and means carried by the loop taker shaft to confine the wad on the ejector rod and to subject the lubricant expressed from the wad to sufficient pressure to reach the loop taker through the loop taker shaft.

9. A lockstitch sewing machine having, in combination, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder comprising a bobbin for a supply of locking thread in the thread case, releasable means for securing the bobbin in the thread case, a hollow shaft on which the loop taker is mounted, an ejector rod slidable in the loop taker shaft and having a portion engageable with the releasable means for ejecting the bobbin from the thread case, a pump for causing lubricant to flow to the raceway in the loop taker, comprising a wad of absorbent material mounted on the ejector rod and means actuated by the rod for expressing lubricant from the wad to force lubricant into the raceway for the thread case, a cylinder on the loop taker shaft to confine the wad on the ejector rod and to subject the lubricant expressed from the wad to pressure, and means for retracting the wad from the cylinder whereby the periphery of the wad is exposed for application of lubricant thereto.

10. A lockstitch sewing machine having, in combina tion, a rotary loop taker formed with an internal raceway, a thread case mounted in the raceway, a holder comprising a bobbin for a supply of locking thread in the thread case, releasable means for securing the bobbin in the thread case, a hollow shaft on which the loop taker is mounted, an ejector rod slidable in the loop taker shaft and having a portion engageable with the releasable means for ejecting the bobbin from the thread case, a pump for causing lubricant to flow to the raceway in the loop taker, comprising a wad of absorbent material mounted on the ejector rod and means actuated by the rod for expressing lubricant from the wad to force lubricant into the raceway for the thread case, a cylinder on the .loop taker shaft to confine the wad on the ejector rod and to subject the lubricant expressed from the wad to pressure, means for retracting the wad from the cylinder whereby the periphery of the wad is exposed, and a conduit having an outlet just above the wad to apply lubricant to the periphery of the wad.

References Cited in the file of this patent UNITED STATES PATENTS 2,323,422 Sauer July 6, 1943 2,395,653 Attwood Feb. 26, 1946 2,507,470 Hirsch May 9, 1950 

